1) If you had 180 ears of corn compared to last year, and the rate of increase was 200%, then the formula for the increase would be: [200% + 1] x C=180, C=last year's number of ear corns. Then just solve for C: [200/100 + 1] x C=180
C=180/3 =60 ears of corns that they had last year.
2) Volume of rectangular pyramid is:
V=[L x W x H] / 3. Just substitute your numbers in the formula and get your answer.